Pressure vessel seal

ABSTRACT

A pressure vessel including a sealing structure for the cover which comprises a triangularly-shaped gasket in sealing engagement with a curved shoulder on the cover, a gasket engaging surface of the vessel wall and a backing ring positioned between the gasket and a key-ring located in a groove in the vessel wall.

United States Patent Smith Related US. Application Data [63]Continuation-in-part of Ser. No. 836,462, June 25, 1969, abandoned.

[52] US. Cl. ..220/46 MS, 220/3, 220/57 [5 1] Int. Cl ..B6Sd 45/00, 365d53/00 [58] Field of Search ..220/46, 3, 57

[56] References Cited UNITED STATES PATENTS 2,903,152 9/1959 Kuo..220/46 MS '[451 Oct. 3, 1972 3,159,302 12/1964 Latham et a1. ..220/46MS Primary Examiner-George T. Hall Attorney-Louis E. Mam et a].

[ ABSTRACT A pressure vessel including a sealing structure for the coverwhich comprises a triangularly-shaped gasket in sealing engagement witha curved shoulder on the cover, a gasket engaging surface of the vesselwall and a backing ring positioned between the gasket and key-ringlocated in a groove in the vessel wall.

8 Chain, 3 Drawing Figures /.9 12 Q 7 um munumm l4 1*; I 2 llllll lllllI III I8 I n mun l l I l7 'j III In u m PATENTEDnma 1972 3.695.482

sum 1 or 2 INVHY'IOR.

Colin Smith ATTORNEYS PATENTEDHBI3 I 2 3.695.482

sum 2 BF 2 Fig. 2.

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INVENTOR.

Colin Smith 77Za/m &

V ATTORNEYS .1 PRESSURE VESSEL SEAL This application is acontinuation-in-part of application Ser. No. 836,462, filed on June 25,I969; abandoned.

This invention relates to high pressure metallic ves sels and inparticular to a sealing structure for sealing a removable closure to awall of the vessel. It is particusure-tight condition. With very highpressures of several thousands of pounds per square inch or more itbecomes almost impossible to seal such a vessel for the lack ofsufficient space for the necessarily large bolts.

Although remedies have been suggested for resisting the high gross loadas for example by shear keys, many of the high pressure coverconstructions have the gasket subjected directly or indirectly to thehigh internal pressure. In most cases, difficulties of effective sealingexist, not only because the gasket deforms under great load, but alsobecause it is difficult to detect any specific point of leakage or totake any steps to correct It.

It is a main object of the present invention to provide a pressurevessel with a sealing structure which avoids the said difficulties.

According to the invention there is provided a pressure vessel having awall surrounding an opening therein, a key-receiving groove extendingaround said wall adjacent to said opening, a gasket-engaging surfaceextending around the wall from the side of the keyreceiving grooveremote from the opening, a key-ring located in said groove and includinga portion which projects from the groove into the vessel, a coverinserted through said opening into the vessel and including a shoulderarranged to face the gasket-engaging surface, a gasket of substantiallytriangular cross-section having one side engageable with thegasket-engaging surface and a second side engageable with said shoulder,and a backing ring engageablewith the third side of the gasket and withsaid projecting portion of the key-ring. The shoulder is preferablycurved towards the gasket-engaging face and the backing ring, and thekey-ring preferably consists of a plurality of segments. The face of thegasket which engages the gasket-engaging face may be outwardly curved.

The pressure vessel also includes a pull-up member located in saidopening, and rotatable pullup elements extending through the pull-upmember and into the cover and arranged to effect tightening and sealingof the gasket against the gasket-engaging surface, the shoulder, and thebacking ring. A portion of the pull'up member is seated on a pull-upmember receiving shoulder in the vessel and another portion of thepullup member is seated on the key-ring, to take up dimensionaltolerances.

The pressure vessel may include a jacking bar which extends across saidopening, which is arranged to be secured to said wall, and which carriesa cover-retaining bolt arranged to be screwed into the cover and to drawthe cover into the initial assembly position thereof.

Jacking screws may be provided with the jacking bar and be operable onrotation thereof in one direction in the bar to engage the outer face ofthe cover and to break the seal between the gasket and the cover.

In order that the invention may be clearly understood one embodimentthereof will now be described, by way of example, with references to theaccompanying drawings, in which:

FIG. 1 is an end elevation of a pressure vessel according to theinvention;

FIG. 2 is a section, with parts broken away, on line II-IIl, FIG. 1; and

FIG. 3 illustrates the cross-section of a gasket which may be used withthe pressure vessel.

Referring to the drawings, the pressure vessel has a wall 1 surroundingan opening 2 therein and a keyreceiving groove 3, FIG. 2, extends aroundthe wall 1 adjacent to the opening 2. A gasket-engaging surface 4 isformed in and extends around the wall 1 from the side 5 of thekey-receiving groove 3 which is remote from the opening 2. Thegasket-engaging surface is outwardly tapered toward the opening 2 tofacilitate insertion and removal of the gasket. A cover 6 is disposed inthe vessel and a key-ring 7 is located in the groove 3 and includes aportion 8 which projects from the groove 3. The key-ring 7 preferablyconsists of a plurality of segments.

A gasket 9 of substantially trangular cross-section has one sideengageable with the gasket-engaging surface 4, a second side which isengageable with a shoulder 10 on the cover 6, and a third side which isengageable with a backing ring 11, which latter is also engageable withthe portion 8 of the key-ring. The shoulder 10 is curved towards thesurface 4 and the backing ring to facilitate initial seating of thegasket 9 and provide point contact between the shoulder 10 and gasket 9.The shoulder 10 is preferably outwardly curved with a radius ofcurvature which is as large as possible to minimize local yielding onthe gasket face. The third side of gasket 9 which is in engagement withthe ring 11 is positioned at an angle greater than with respect tosurface 4 to assist in the radial displacement of gasket 4 uponapplication of pressure.

A pull-up member in the form of a pull-up ring 12 is located in theopening 2 and rotatable pull-up elements, shown as bolts 13, extend]through the pull-up ring 12 and into the cover 6 and are provided withnuts 14 which on rotation thereof in one direction effect an initialtightening and seating of the gasket 9 against the gasket-engagingsurface 4, the shoulder 10, and the backing ring 11.

The pull-up ring 12 is provided with a circular flange 33 which isseated on a pull-up ring receiving shoulder 19 which extends around thewall 1 between keyreceiving groove 3 and opening 2. The lower portion ofpull-up ring 12 is provided with a circular shoulder 35 which is adaptedto seat on the portion of surface 36 of key-ring 7 which projects fromkey-receiving groove 3. In this manner, upon seating the gasket,dimensional tolerances are taken up thereby preventing any movement ofthe closure structure; i.e., upon seating the gasket, the cover 6,gasket 9, backing ring 11, key-ring 7 and pull-up ring 12 are drawn intorespective engagement with each other, with inward movement beingprevented by seating of flange 33 against shoulder 19 and outwardmovement being prevented by seating of the surface 36 of key-ring 7against the upper surface of key-receiving groove 3.

A jacking bar 15 extends across the opening 2 and is secured by bolts 16to the wall 1 of the vessel, and the bar 15 carries a cover-retainingbolt 17 which is screwed into the cover 6 and which is arranged to drawthe cover into the initial assembly position thereof. Jacking screws 18are also provided with the jacking bar 15 and are operable on rotationthereof in the bar 15 to engage the outer face of the cover 6 and tobreak the seal between the gasket 9 and the shoulder 10 of the cover 6.

When assembling the apparatus, the cover 6 is inserted into the opening2 in the wall 1 and the gasket 9 is placed in position. The backing ring11 is inserted on the gasket andthen the segments of the key-ring 7 arelocated in the groove 3. The pull-up bolts 13, except those which willunderlie the jacking bar, are screwed into the cover 6 and then thepull-up ring 12 is placed over the bolts 13 to rest against shoulder 19on wall 1. The jacking bar 15 is now placed in position and secured bythe bolts and cover-retaining bolt 17 is screwed into the cover 6 andnut 20 on bolt 17 is rotated to draw the shoulder 10, gasket 9, andbacking ring 11 into engagement against the portion 8 of the key-ring.

Next the nuts 14 are applied to the pull-up bolts 13 and are rotated toeffect the desired seating of the gasket 9 against the shoulder 10, thesurface 4, and the backing ring 11. The backing ring 11 ensures that aneven, uninterrupted, pressure is exerted on the gasket on the sidethereof which is engaged by the backing ring.

At the point where the gasket 9 seats against the surface 4 a bearingload exists but the bearing stress across the surface 4 is restricted toa safe limit and as the area available for shear in the wall 1 isexcessive in a plane at right angles to the surface 4 no local yieldingtakes place in the vessel and the load is dispersed over a large area.If the vessel is raised to its full test pressure and the pressure isthen released, a leaking joint will occur if yielding of the gasket 10has exceeded the compressing elastic limit. Should such yielding occurthere will be a slackening of the pull-up bolts 13 and tightening of thebolts 13 will serve to retain a pressure-tight seal.

When dismantling the apparatus, the studs 13 which lie in the path ofthe jacking bar 15 are removed, the jacking bar is secured in position,and the jacking screws 18 are screwed into engagement with the cover.The remaining studs 13 are then removed and the jacking screws 18 arerotated to break the seal between the cover and the gasket. The jackingbar is now removed and, following removal of the pull-up ring 12, rods,not shown, are pushed into holes 21 to push out the key-ring sections.The jacking bar is again secured in position and its screw 18 screwedinto the cover. The backing ring and gasket can now be removed, as canthe cover.

' If desired, instead of the gasket 9 having three flat sides in FIG. 2,the side which is to engage the gasketengaging surface 4 may beoutwardly curved as shown at 22, FlG.3.

The present invention is particularly advantageous as a result of thefollowing features:

1. The use of a triangular gasket 2. The point contact between thegasket and the cover; i.e., the gasket face is straight and the coverseat is curved.

3. The angular positioning between the gasket-engaging face of thevessel wall and the surface of the gasket which is in engagement withthe backing ring, which facilitates radial displacement of the gasketupon application of pressure.

4. The outward taper of the gasket-engaging surface of the vessel wallwhich facilitates placement of the gasket.

5. The relationship between the pull-up ring and keyring which takes updimensional tolerances to thereby prevent movement of the closurestructure.

Numerous modifications and variations of the present invention arepossible in light of the above teachings and, therefore, within thescope of the appended claims the invention may be practiced other thanas particularly described.

What is claimed is:

I. An apparatus comprising: a pressure vessel having a wall surroundingan opening therein, a key-receiving groove extending around said walladjacent to said opening, a gasket-engaging surface extending around thewall at the side of the key-receiving groove remote from the opening, akey-ring located in said groove and including a portion which projectsfrom the groove into the vessel, a cover inserted in said opening in thevessel and including a shoulder having a surface outwardly curvedtowards the gasket-engaging surface, a gasket of substantiallytriangular cross-section having one side in sealing engagement with thegasket-engaging surface, the second side in sealing engagement with saidoutwardly curved surface of said shoulder and the third side facing saidkey-ring a backing ring positioned adjacent to said wall between thekey-ring and the third side of the gasket, said backing ring being insealing engagement with the third side of the gasket and the keyring.

2. The apparatus as claimed in claim 1 wherein said gasket engagingsurface extends angularly outwardly toward said opening to facilitateremoval of the gasket.

3. The apparatus as claimed in claim 1 wherein the third side of thegasket which is in sealing engagement with the backing ring ispositioned at an angle greater than with respect to the gasket engagingsurface around said'wall.

4. The apparatus as claimed in claim 1 and further comprising a pull-upmember positioned in the opening; rotatable pull-up means extendingthrough the pull-up member into the cover; a pull-up memberreceivingshoulder extending around the wall between the key-receiving groove andsaid opening, an upper portion of said pull-up member being seated onsaid pull-up receiving'shoulder and a lower portion of said pull-upmember being seated on the portion of the keyring which projects fromthe groove, whereby rotation of the pull-up means effects tightening andseating of the gasket and takes up dimensional tolerances.

5. The apparatus as defined in claim 4 and further comprising a jackingbar which extends across said opening and is secured to said wall, and acover retaining rotatable bolt extending through the jacking bar andscrewed into the cover, whereby rotation of said bolt draws the coverinto initial assembly position.

the outer face of the cover and to break the seal between the gasket andthe cover.

7. An apparatus comprising: a pressure vessel having an open end, akey-receiving groove extending around the interior surface of saidpressure vessel adjacent to the open end, a gasket-engaging surfaceextending around the interior surface of the vessel adjacent the side ofthe key-receiving groove remote from the open end of said vessel, akey-ring located in said groove and including a portion which projectsfrom the groove into the vessel, a cover inserted in said vessel toclose the open end thereof, the outer portion of the cover at the openend of the vessel, including an outwardly curved shoulder arranged toface the gasket-engaging surface, a gasket of substantially triangularcross-secton extending around the interior surface of the vessel, saidgasket having one surface in sealing engagement with the gasket-engagingsurface, a second surface in sealing engagement with said shoulder and athird surface facing said key-ring, a backing ring extending around theinterior surface of the vessel positioned between the keyring and thethird side of the gasket, said backing ring having a first surface inengagement with said gasketengaging surface extending around theinterior surface of the vessel, a second surface opposite said firstsurface adjacent to and spaced form said cover, a third surface inengagement with said key-ring and a fourth surface opposite said thirdsurface in sealing engagement with the third surface of the gasket.

8. The apparatus as claimed in claim 7 and further comprising a pull-upmember positioned in the opening; rotatable pull-up means extendingthrough the pull-up member into the cover; a pull-up member receivingshoulder extending around the wall between the key-receiving groove andsaid opening, an upper portion of said pull-up member being seated onsaid pull-up receiving shoulder and a lower portion of said pull-upmember being seated on the portion of the keyring which projects fromthe groove, whereby rotation of the pull-upmeans effects tightening andseating of the gasket and takes up dimensional tolerances.

1. An apparatus comprising: a pressure vessel having a wall surroundingan opening therein, a key-receiving groove extending around said walladjacent to said opening, a gasket-engaging surface extending around thewall at the side of the keyreceiving groove remOte from the opening, akey-ring located in said groove and including a portion which projectsfrom the groove into the vessel, a cover inserted in said opening in thevessel and including a shoulder having a surface outwardly curvedtowards the gasket-engaging surface, a gasket of substantiallytriangular cross-section having one side in sealing engagement with thegasket-engaging surface, the second side in sealing engagement with saidoutwardly curved surface of said shoulder and the third side facing saidkey-ring a backing ring positioned adjacent to said wall between thekey-ring and the third side of the gasket, said backing ring being insealing engagement with the third side of the gasket and the key-ring.2. The apparatus as claimed in claim 1 wherein said gasket engagingsurface extends angularly outwardly toward said opening to facilitateremoval of the gasket.
 3. The apparatus as claimed in claim 1 whereinthe third side of the gasket which is in sealing engagement with thebacking ring is positioned at an angle greater than 90* with respect tothe gasket engaging surface around said wall.
 4. The apparatus asclaimed in claim 1 and further comprising a pull-up member positioned inthe opening; rotatable pull-up means extending through the pull-upmember into the cover; a pull-up member-receiving shoulder extendingaround the wall between the key-receiving groove and said opening, anupper portion of said pull-up member being seated on said pull-upreceiving shoulder and a lower portion of said pull-up member beingseated on the portion of the key-ring which projects from the groove,whereby rotation of the pull-up means effects tightening and seating ofthe gasket and takes up dimensional tolerances.
 5. The apparatus asdefined in claim 4 and further comprising a jacking bar which extendsacross said opening and is secured to said wall, and a cover-retainingrotatable bolt extending through the jacking bar and screwed into thecover, whereby rotation of said bolt draws the cover into initialassembly position.
 6. The apparatus as defined in clam 5 and furthercomprising jacking screws in the jacking bar, said jacking screws beingrotatable within the bar to engage the outer face of the cover and tobreak the seal between the gasket and the cover.
 7. An apparatuscomprising: a pressure vessel having an open end, a key-receiving grooveextending around the interior surface of said pressure vessel adjacentto the open end, a gasket-engaging surface extending around the interiorsurface of the vessel adjacent the side of the key-receiving grooveremote from the open end of said vessel, a key-ring located in saidgroove and including a portion which projects from the groove into thevessel, a cover inserted in said vessel to close the open end thereof,the outer portion of the cover at the open end of the vessel, includingan outwardly curved shoulder arranged to face the gasket-engagingsurface, a gasket of substantially triangular cross-secton extendingaround the interior surface of the vessel, said gasket having onesurface in sealing engagement with the gasket-engaging surface, a secondsurface in sealing engagement with said shoulder and a third surfacefacing said key-ring, a backing ring extending around the interiorsurface of the vessel positioned between the key-ring and the third sideof the gasket, said backing ring having a first surface in engagementwith said gasket-engaging surface extending around the interior surfaceof the vessel, a second surface opposite said first surface adjacent toand spaced form said cover, a third surface in engagement with saidkey-ring and a fourth surface opposite said third surface in sealingengagement with the third surface of the gasket.
 8. The apparatus asclaimed in claim 7 and further comprising a pull-up member positioned inthe opening; rotatable pull-up means extending through the pull-upmember into the cover; a pull-up member receiving shoulder extendingaround the wall betweeN the key-receiving groove and said opening, anupper portion of said pull-up member being seated on said pull-upreceiving shoulder and a lower portion of said pull-up member beingseated on the portion of the key-ring which projects from the groove,whereby rotation of the pull-up means effects tightening and seating ofthe gasket and takes up dimensional tolerances.